Telescoping shelf assembly

ABSTRACT

A lightweight, sturdy, shelving assembly is disclosed, having telescoping metal shelf and guard rail units which snap fit between (right and left) end brackets, provided with hook ends at their bases to engage spaced upright slotted rails. The lateral span of the shelving assembly is adjustable to fit the desired space. The vertical spacing between the shelves and their guard rails is adjustable after installation to accommodate different sizes of articles. The shelf units are identical pairs having slotted box flanges, one larger than the other, which telescope together with the larger flange receiving the smaller flange of each as the planar surfaces overlap. Each have rolled front and rear box flanges and are identical. The guard rail units are identical pairs formed as rolled poly-sided beams. Each beam has an open-ended slot along one corner whereby two such units, oriented 180* from each other along their longitudinal axes, receive on another in telescoping relationship, with the slot of each receiving a continuous wall of the other. The distal ends of the guard rail brackets have tabs snap-engaging the open extended ends of the guard units. The shelf brackets are provided with a supporting inner flange having distal tabs engaging appropriate openings in the inside walls of the ends of the box flanges of the shelf units.

United States Patent [191 Ferdinand et al.

[ Oct. 16, 1973 TELESCOPING SHELF ASSEMBLY [75] Inventors: Irwin J.Ferdinand, Glencoe; Irwin R. Kulbersh, Morton Grove, both of I11.

[73] Assignee: The Hirsh Company, Skokie, Ill.

[22] Filed: May 15, 1972 [21] Appl. No.: 253,317

Primary Examiner-James T. McCall Assistant Examiner-Kenneth J. DornerAtt0rneyWatson D. I-larbaugh et a1.

[57] ABSTRACT A lightweight, sturdy, shelving assembly is disclosed,having telescoping metal shelf and guard rail units which snap fitbetween (right and left) end brackets, provided with hook ends at theirbases to engage spaced upright slotted rails. The lateral span of theshelving assembly is adjustable to fit the desired space. The verticalspacing between the shelves and their guard rails is adjustable afterinstallation to accommodate different sizes of articles. The shelf unitsare identical pairs having slotted box flanges, one larger than theother, which telescope together with the larger flange receiving thesmaller flange of each as the planar surfaces overlap. Each have rolledfront and rear box flanges and are identical. The guard rail units areidentical pairs formed as rolled poly-sided beams. Each beam has anopen-ended slot along one corner whereby two such units, oriented 180from each other along their longitudinal axes, receive on another intelescoping relationship, with the slot of each receiving a continuouswall of the other. The distal ends of the guard rail brackets have tabssnap-engaging the open extended ends of the guard units. The shelfbrackets are provided with a supporting inner flange having distal tabsengaging appropriate openings in the inside walls of the ends of the boxflanges of the shelf units.

20 Claims, 11 Drawing Figures 1 TELESCOPI-NG SHELF ASSEMBLY RELATEDPATENTS BACKGROUND OF THE INVENTION The tray shelving of U.S. Pat. No.2,982,423 can be easily assembled and dis-assembled, and provides bothinternal and external bracing with dividers for reinforcing andstability. This shelving is suited for longevity under conditions ofheavy use. A telescoping arrangement of non-identical guard rails andtrays is disclosed with the end walls having ears with extensions thatengage spaced elongated slots in the connecting wall ofa U-shapedvertical support element.

The tray shelving of U.S. Pat. No. 3,139,258 can likewise be easilyassembled and adjusted due to the upper and lower coplanar ears andtheir extensions on the bracket elements cooperating with the spacedslots in the inverted channel portion of the support elements. Here alsomale and female telescoping guard rails and shelf units are disclosed.

SUMMARY OF THE INVENTION The instant invention comprises certainimprovements and simplifications over the structures shown in said priorpatents, wherein full advantage of the telescoping feature of theshelves and guard rails is attained without multiplying the number ofparts involved, and at the same time, reducing the number of steps inthe manufacture while retaining the strength, rigidity and ease ofassembly. This is accomplished by fabricating the shelf and guard railin'identical pairs so that, though the pairs of shelf parts telescopealong their flanges, the appearance of the shelf externally is that of asingle unit. Likewise, the guard rail units fit together in such amanner that the cross-sectional configuration of the telescoped portionsis hardly larger than the extending untelescoped portions. Not only arethe parts easily assembled in their telescoping relationship, therigidity of the telescoping parts is enhanced while their attachment tothe respective brackets is facilitated.

DESCRIPTION OF THE DRAWINGS An embodiment of the invention is shown inthe drawings wherein:

FIG. 1 is a perspective view of an assembled series of three shelves andguard rails;

FIG. 2 is a partial'cross-sectional view along the line 22 of FIG. 1;

FIG. 3 is a fragmentary cross-sectionalviewalong the lines 3--3 of FIG.2;

FIG. 4 is a fragmentary cross-sectional view along the lines 4-4 of FIG.2;

FIG. 5 is a cross-sectional view along the lines 55 of FIG. 3;

FIG. 6 is a cross-sectional view along the lines 6-6 of FIG. 4;

FIG. 6A is an end view of one of the guard rail units to show the spacedrelationship of the walls in better detail;

FIG. 7 is a fragmentary perspective view illustrating the manner ofattachment of one end of the shelf to one of the support brackets;

FIG. 7A is a plan view of a blank sheet of metal from which a shelf unitis formed;

FIG. 8 is an exploded view of an embodiment of this invention toillustrate the general organization of the parts; and 7 FIG. 8A is afragmentary enlarged perspective view of the end of one of the guardrail brackets to show the tabs in more detail.

THE PREFERRED EMBODIMENT Referring to FIG. 1 a shelf assembly as showncomprising the pair of upright supports or rails 12 having end caps 14,attached in selected spaced vertical relationship upon the supportingwall 16, the pair of guard rail brackets 20 and 20, the guard railassembly 22, the pair of shelf brackets 24 and 24' and the shelfassembly 26. The remaining bracket, guard rail and shelf assemblies ofFIG. 1 are for the purpose of illustrating that any member of said unitscan be attached to a given pair of upright supports 12 and the distancebetween a shelf and its guard rail, a shelf and the guard railthereunder and the over-all vertical spacing of the units are subject tovariation as desired in accordance with the placement in relation to thevertical slots 28 (see FIG. 8) in the rails.

The rails 12 are generally U-shaped in cross-section to include theparallel spaced side walls 30 and 32 (FIG. 8), the pair of spacedcoplanar front walls 34 and 36, joined by the arcuate connecting wall 38which has the slots 28 cut therein at desired equally spaced intervals.The bracket member 40 is illustrative of means for attaching the railsto wall or other planar supporting surfaces in a manner which is simpleand allows the entire assembly to be easily taken down or rearrangedlaterally to accommodate different sizes of articles. The wall bracketmember 40 comprises the fiat base 42 integral with the projecting sidewalls 44, of equal depth, and the hook member 46 located substantiallycentrally between the side walls 44 and projecting outward from the base42 a distance sufficient to engage a rail slot 28 with the upright hookportion 48 thereof engaged on the frontal top edge of said slot. A woodscrew 50 serves to hold the wall bracket to the wall. The side walls 44fit inside the walls 30-32 of the rails and abut against the insidesurfaces of the intermediate walls 34-36 ina locked supportingrelationship (see FIG. 2). The wall bracket member 40 does not form apart of this invention and any means can be used to fasten the uprightsto the walls. A bracket 40 or the equivalent is used at the top andbottom of each of the rails 12 in order to orient same flush against thewall 16 in weightsupporting vertical parallel relationship. The uprightsare readily removed by sliding them upward to disengage the hook 48 fromthe slot 28 which is longer than the vertical height of the flat hookmember 46.

Another optional and commonly used part of the assembly is the end plug14, formed of molded plastic, which fits into the open ends of theuprights as a finish trim piece. Various designs of these end plugs areknown in the art provided with tabs 52 which engage within the openchannels between the walls 30 and 32 in a snap-fit relationship.

The guard rail brackets 20 and 20' may be formed of any material and forpurposes of combined strength and lightness are formed of tough plastic.As shown in FIGS. 2 and 8 the right hand guard rail bracket comprises anelongated arm 54 having the transverse shoulder or boss 56 with a flatend or inside surface 58 from which extends the shank portion 60 havingthe upstanding tab or hook 62 and the lower tab or hook 64. The inneredges 66 and 67 of the hooks 62 and 64, respectively, are coplanar andnormal to the longitudinal axis of the arm 54.

Referring to FIGS. 2 and 4, it is apparent that the bracket 20 is easilyattached during insertion of the tab 62 into a slot 28, by tilting thearm 54 so that the tab 62 clears the top and bottom edges of the slot28. Then, as the arm 54 is pivoted to the horzontal and moveddownwardly, the lower hook 64 engages over the bottom edge of the slot28. The tab 62, being longer, still engages behind the wall 38 at thetop of the slot. At the same time, since the distance between the insidesurface 58 of the flange 56 and the inner surfaces 66 and 67 of bothtabs 62 and 64 is substantially the same as the spaced relationship ofthe front walls 34-36 from the inner surface of the wall 38, the bracketis squared to the rail and extends rigidly therefrom.

At the distal end of the arm 54, and spaced from the end, top and bottomedges, there is provided a pair of tabs 72-74, facing normal to theinner side (FIGS. 2 and 8) which engage in a force fit relationshipwithin the open end 76 of one member 78 of the guard rail assembly 22.The cross-sectional area of the opening 76 is no greater than the spacearea around the tabs 72 and 74 so that the end edges of the member 78abut against the arm 54 and are not exposed. The guard rail bracket 20'is the mirror image of bracket 20 in order to form the support for theother end of the guard rail assembly 22. Consequently, the details ofits structure need not be set forth or can be inferred from thedescription of bracket 20.

In FIG. 8 the tabs 72 and 74 are illustrated as being essentiallyrectilinear spaced equal sized protuberances extending from the insidesurface of the arm 54, near the end thereof. Since the guard rails 78are made of rolled sheet metal the walls thereof have a certainresiliency at the open end and the pair of tabs 72 and 74, made ofplastic, are readily sized so as to snap-fit into the open end 76. Sincethe hook 62 is held by the U- shaped wall 38 against lateral thrust, theguard rail brackets 20 and 20 are substantially rigid once affixed inthe rails 12. The guard rail assembly 22 can thus be extended to fitbetween the distal ends of the pair of guard rail brackets and be heldby the tabs 72 and 74 against displacement.

A modification of this structure is shown in FIG. 8A wherein the end ofthe arm 54 is provided with spaced tabs 80 and 82 which have oppositelycurved tips 84 and 86 which function to engage the inner edges of theopening 76 causing a simultaneous spreading action on the walls and acompression action on the tabs as they are inserted. Also, the fourbosses 88 are provided in spaced corner relationship around the base ofthe tabs 80 and 82 to form a margin against the outer surfaces of thewalls of the guard rail unit 78 and further prevent lateral or verticaldisplacement. The effective outside area of the spaced curved ends 84-86is slightly greater than the unsprung area of the opening 76. while theeffective inner area between the bosses 88 is slightly greater than orsubstantially equal to the outer sprung area of the end of each guardrail unit 78. The open ends 76 are thus subject to combined andcooperating expanding and contracting forces to form a solid seatagainst the inside of the arms 54. The guard rail bracket 20' would besimilarly modified in this embodiment although it is apparent that themodified guard rail brackets are inter-changeable with that shown inFIG. 8.

As shown in FIGS. 6 and 8, the members 78 and 78 comprising the guardrail assembly 22 are identical. In FIG. 6 these members are shown intelescoping relationship while FIG. 6A shows an end view of one of therail members so that the walls thereof and their spacing can beidentified. It is to be understood that the guard rails 78 and 78' onceassembled or telescoped can be used in any quarter-turn orientation toreceive the tabs 72 and 74 on tabs and 82 in the openings 76.

Referring to FIG. 6A an end of the guard rails 78 (or 78) is shown toinclude an internal partial wall 90, the interconnecting side walls 92,94, 96 and 98 with the latter having a rolled-over edge portion 100. Thewalls 94, 96 and 98 are of substantially equal width and the sum of thecombined thickness of the wall 98, its rolled over-portion 100, thespace 102, between it and the partial wall 90, and the width of the wall92 is about the same as the wall 96 so that an essentially squareconfiguration is formed. Uniformity in wall width or an exactly squareconfiguration is not essential to the invention and it is obvious thatin roll-forming a tubular member such as this that all of the cornerswill not or need not be 90 angles. The edge of the wall 90 terminatesshort of the inside surface of the wall 96 as indicated by the space104, which like the space 102, is at least as great as and preferablyslightly greater than the thickness of the sheet metal used in thefabrication. It is apparent that some latitude in these spaces ispermissible because all of the walls have a spring action along theirlengths. The end view of FIG. 6A may also represent a cross-sectionalconfiguration of these wall parts at any point along the length of thesemembers. Although a square or rectangular configuration has beenillustrated, these parts may be fabricated in any tubular configuration.The opening 76 extends the entire length of the guard rail members forinterconnecting telescoping relationship as will be described inreference to FIG. 6.

In FIG. 6, there is shown the relationship of the walls of a pair oftelescoped guard rails 78 and 78. For simplicity not all of the walls ofthe guard rail 78 bear reference numbers and in the followingdescription reference to FIG. 6A can be made to identify the parts. Itis seen that the internal partial wall 90 of guard rail unit 78' isinside and oppositely oriented to the wall 90 of guard rail 78. The wall92 passes through the space 104 and the wall 94' extends between thewalls 90 and 98 through the space 102, while the wall 96' emerges andwith wall 98 completes the configuration. The wall 94 of guard rail unit78 passes through the space between the wall 98' and 92. The space 106has been correspondingly reduced in size over the end space or opening76.

It is also apparent from FIG. 6 that two outside walls of-each of thetelescoped guard rail units, which constitute the guard rail assembly 22present two adjacent walls on the outside. Accordingly, by grasping theguard rail assembly with the finger tips of one hand against an adjacentpair of these walls and the fingers of the other hand against the otherpair of walls and moving the hands in opposite axial directions asindicated by the arrow 108 (FIG. 8), the length of the guard railassembly can be adjusted to the desired amount. In this manner, after apair of guard rail supports 20 are attached to the desired slots 28 inthe rails 12, the tabs 72 and 74 (or 80 and 82) thereon are readilypressed into the openings 76 at each end, in the manner shown in FIGS. 1and 4.

The shelf brackets 24 and 24', like brackets 20 and 20 are identical butopposite, being mirror images of each other. The description of one willsuffice for both. In FIGS. 2, 7 and 8 it is seen that the bracket 24 hasthe arm 110 extending normally from the base flange 112, the back side 114 of which is flat and normal to the longitudinal axis of the arm 110.The base flange 112 is about the same width as the rail 12 and has theprotruding shank 116 central of the rear side 114 with the downwardprojecting hook 118 formed thereon. The arm 1 projects from the inneredge of the base flange 112. The inner edge 120 of the hook 118 isparallel to the back side 114 and spaced therefrom a distance aboutequal to the thickness of the rail between the back side of the wall 38and the front walls 34-36. The outer surfaces of the arm 1 10 areprovided with a rectangular trim flange 122 defining a planar surface124 into which a trim panel of wood grained plastic (not illustrat'ed)is applied by means of pressure-sensitive adhesive, if desired.

The inside portion of the arm 110 of each bracket 24 has peripheralreinforcing edge flange 126 and the supporting flange 128 extendingnormal to the vertical plane of the arm 110 and also normal to the baseflange 112. The forward end of the flange 128 .is notched at 130 to formthe distal tab 132. The end of the tab 132 is spaced from the extendedend 134 of the arm 110. The tab 132 is also spaced from the top andbottom flanges 126 of the arm 110. The flange 128 has a number of markerribs 136 therealong for the purpose of identifying the spacedorientation of the bracket during assembly.

The back end of the flange 128 extends beyond the base flange 112 andthe extended end carries the transverse abutment flange 138 spaced fromthe end. At this inner edge the notch 140 defines the rearward distaltab 141 in line with the other tab 132. The distance between the notches130 and 140 is about the same as the effective distance between the boxflanges of the shelf assembly as will'be described.

Referring to FIGS. 3, 5 and 7 it is seen that the shelf assembly 26comprises a pair of identical shelf units indicated by the numerals 142and 142', which units are identical, each having square ends indicatedat 144 with longitudinal side box flanges 146 and 148 bordering theobject supporting planar rectangular portion 150. For simplicity thefurther details of the shelf unit 142 will be described, it beingunderstood that the description also applies to the shelf unit 142.

The side box flanges 146 and 148 are identically formed but oppositelyturned or rolled in'relation to the planar portion 150, except that thecross-section outside area of one of the flanges, i.e., the box flange148 is smaller than or about the same as the cross-sectional inside areaof the box flange 146. As will be explained, the smaller box flange ofone shelf unit fits into the larger box flange of another shelf unit,the latter being reversed end for end to accomplish this, in slidingtelescoping relationship.

FIG. 7A shows a plan view of a rectangular sheet metal blank which hasbeen pre-punched or cut to provide the proper relationship of certainopenings which are used to hold the shelf to the shelf brackets 24 and24'. The sheet metal blank provides the planar surface 150 and bothsides of the blank including the side borders are finished with thedesired coating or paint to produce a simulated wood or other paintedsurface.

The parallel, spaced broken lines, i.e., the lines 151 and 152 in therespective side borders indicate the fold lines for the formation of thebox flanges 146 and 148. Prior to folding, the blank has eight openingsformed in the side borders which become oriented adjacent to the planarsurface and on opposite sides thereof when the formation of the boxflanges is completed.

For purposes of illustration, FIG. 7A is oriented between FIGS. 7 and 8,as if to form the shelf unit 142 therefrom. Accordingly, the lower sideborder will be used to form the larger box flange 146 while the top sideborder will be used to form the smaller box flange 148. The spacingbetween the fold lines 152 is slightly greater than the spacing betweenthe fold line 151 to accomplish this purpose.

The sheet metal blank is cut to provide the notch openings 154 and 156at the edge 158 and the notch openings 160 and 162 at the edge 164.These notch openings are illustrated as rectangular but it is to beunderstood that any shape of opening can be used. At the innermost foldlines of each side border, four more openings are provided, namely, therectangular openings 166 and 168 for the box flange 148 and therectangular openings 170 and 172 for the box flange 146.

The larger box flange 146 is formed from the bottom side portion of theblank by folding the metal mechanically along the respective fold lines152 such that the edge 164 (see FIG. 7) defines the elongated space orslot 174 between it and the planar surface 150 thus producing the innerside wall 176, the top wall178 (see FIG. 8), the outer wall 180, thebottom wall 182 and the inner wall 184, the latter being formed alongthe innermost of the form lines 152 whereby it is continuous with theplanar portion 150.

Similarly, the smaller box flange 148 is formed from the top sideportion of the blank by folding the metal mechanically along therespective fold lines 151 in the opposite direction in relation to theflange 146 such that the edge 158 defines the elongated space or slot186 between it and the planar surface 150 thus providing the inner sidewall 188. the bottom wall 190, the outer wall 192, the top wall 194 andthe inner wall 196, the latter being formed along the innermost of theform lines 151 whereby it is continuous with the planar portion 150.

In the box flange 146, the inner walls 176 and 184 are essentiallycoplanar as are the inner walls 188 and 196 of the box flange 148 andboth have the respective slots 174 and 186 on opposite sides. Each shelfunit is, by the opposite folding of the box flanges, provided with eightapertures or openings that are oriented adjacent to but equally spacedfrom each end of the shelf unit. Thus the notch 154 appears on thebottom of the shelf unit 142 in FIG. 7, within the wall 188 of thesmaller flange 148 while the opening 166 does not appear, it being inthe wall 196 immediately above and appearing in FIG. 8. The oppositeopening 170 in the wall 184 is shown in broken lines in FIG. 7 and doesnot appear in FIG. 8. The opening 160 is on the top side of the shelfunit 142 in FIG. 8 being in wall 176, and opposite the opening 166 whichis in the wall 196.

Since the shelf unit 142 is shown telescoped with the shelf unit 142' inFIGS. 7 and 8, the notches or openings 156, 168, 172 and 162 at theother end are hidden and in a non-functional position. However, whenpartially extended, the end notches and openings of the shelf unit 142'are exposed as will be described.

Accordingly, when the smaller box flange 148 of the shelf unit 142 istelescoped within the larger box flange 146 of the shelf unit 142' andsimultaneously the larger box flange 146 of the shelf unit 142 istelescoped over the smaller box flange 148' of the shelf unit 142, theexposed notches and openings of the latter will be oriented as indicatedin FIG. 7. Only the lower or underneath pair of notches at one end ofone shelf unit and the lower or underneath pair of notches at the otherend of the other shelf unit of an assembly 26 are used in attaching theassembly to the shelf brackets 24-24. To telescope the shelf unitstogether one of them is turned end-for-end and fitted into the other asillustrated.

The telescoped relationship of the shelf units 142 and 142' isillustrated in FIG. wherein the smaller box flange of each shelf unit iswithin the larger box flange of the other and the slot defined by theedge 164 of the shelf unit 142 allows the passage of the planar portion150' of the shelf unit 142' and the slot defined by the edge 158' of theshelf unit 142' allows the passage of the planar portion 150therethrough. For simplicity the various walls of the box flanges arenot indicated by numerals in FIG. 5. Thus, at any over-lapping portionof the shelf units, as represented by FIG. 5, the outer walls of thelarger of the box flanges of each shelf unit are totally exposed forgripping with the fingers on each side and moving one shelf unit withrespect to the other to adjust the length thereof. Such an assembly isreadily attached to the fixed brackets 24, by first adjusting the lengthto span squared ends 144 between a pair of the fixed brackets 24-24 heldby the rails 12 to a wall. Then it is only necessary to spread thebottom portions of the flanges at each end of the telescoped unit sothat the holes 170 and 154 at one end can encompass the tabs 132 and 141at the ends of the supporting flange 128 with the end edge flush againstthe arm 110 and the flat portion 150 resting on top of the flange 128.Correspondingly the holes 154' and 160' of the extended end of the othershelf unit are spread to encompass the tabs of the bracket at the otherend. The flanges are readily spread by gripping the shelf in one handwith an inner twisting action at the top of the flanges.

An advantage of this invention is that both the shelf units and guardrails can be packaged and shipped in telescoped condition which takesless shipping space and also makes quick assembly and attachment to thebrackets an easy operation. Also a guard rail assembly 22 affixed to itspair of brackets 24 or a shelf assembly affixed to its pair of bracketscan be moved to and from any desired position between the rails merelyby lifting and tilting these assemblies upwardly and placing them in anew pair of slots.

The invention is not to be limited to any of the dimensions of the partsdescribed herein since it is apparent that both larger and smaller shelfunits and guard rail units can be fabricated following the teachings ofthe specification. Although sheet metal and plastic have been mentionedas the materials of construction,

it is equally apparent that other resilient materials can be used tofabricate the parts. By resilient sheet material" is meant materialwhich can be deformed or bent slightly with ordinary hand pressure orsqueezing in order to spread the flanges sufficiently to engage thebrackets and affix the shelf units or telescoped shelf assembliesthereto. More or less than a pair of shelf units and guard rail unitscan also be used in the assembly of the combination of parts. Forinstance, by telescoping three shelf units together longer spans betweenthe brackets can be accommodated. Actually, one shelf unit 142 and oneguard rail unit 78 can be used to form a shelf assembly if desired. Itmatters not which way the telescoped guard rails or shelf units aremoved in relation to one another since the open ends 76 of the guardrails are uniform and a pair of lower opposite openings will be exposedat either ends of the shelf units. Although openings or notches havebeen disclosed as the means to attach the shelf units or telescopedshelf assemblies to the brackets it is to be understood that any meansoperative to attach the shelf units or an exposed end thereof to thebrackets may be used. Also the manner of attachment of the guard railscan be modified.

What is claimed is:

1. A shelf assembly including:

a shelf unit of resilient sheet material having a rectangular planarportion between coextensive integral tubular flanges along thelongitudinal edges thereof;

each of said flanges extending above and below the plane of said planarportion and presenting internal opposing walls on each side thereof;

apertures in each of said internal walls adjacent to and substantiallyequally spaced from the ends of said shelf; and

a pair of bracket members having arm portions adapted to be affixed inhorizontal spaced coplanar positions from a supporting structure;

said bracket members each having a pair of transversely extending tabson the inner surfaces of said arm portions adapted to span between andengage within said apertures; and

the resiliency of said shelf unit allowing the effective transverse spanbetween said flanges to be spread so as to engage said apertures oversaid pairs of tabs.

2. A shelf assembly in accordance with claim 1 wherein:

a pair of said shelf units is provided as a shelf assema tubular flangeon one side of each of said shelf units being smaller in cross-sectionalarea than the other flange;

the internal opposing wall of said smaller flange having an edgedefining an elongated open-ended slot along one side of said planarportion;

the internal opposing wall of said other and larger flange having anedge defining an elongated openended slot along the opposite side ofsaid planar portion;

said pair of shelf units being telescoped one upon the other with thesmaller flange of one inside the larger flange of the other and saidrespective slots receiving the integral planar portion of the otherwhereby the effective length of said shelf assembly is adjustable.

3. A shelf assembly in accordance with claim lincluding:

a second pair of bracket members having armportions adapted to beaffixed in horizontal spaced coplanar positions from said supportingstructure above said pair of brackets for: said shelf unit, with theextended ends thereof substantially coextensive therewith;

said second pair of brackets each having tab members extending inwardlyfrom the inside and extended end of said arm portions along alongitudinal axis of said shelf unit; and

a tubular guard rail unit adapted to span between and engage at its openends over said tab members of said pair of bracket members.

4. A shelf assembly in accordance with claim 1 in which:

spaced upright substantially coplanar rail members are provided in fixedpositions on said supporting surface to hold said shelf assembly;

said rail members each representing a pair of upright spaced walls withan inwardly offset connecting wall therebetween;

a series of spaced slots in said connecting wall; and

said bracket members include a base flange at one end of said armportion with hook means extending therefrom; 7

said hook means including a downwardly projecting portion the effectivelength thereof being longer than the vertical opening of said slots andthe inner surface of said projecting portions being spaced from saidbase flange substantially the same distance as the offset of saidconnecting wall from said pair of upright walls whereby said hook meansof said bracket members are engageable through said slots in an upwardangular position and said inner surface thereof engages over the bottomof said slots with said base flange abutting same pair of upright wallsof said rail members.

5. A shelf assembly in accordance with claim 3 in which:

spaced upright substantially coplanar rail members are provided in fixedpositions on said supporting surface to hold said shelf assembly;

said rail members each presenting a pair of upright spaced walls with aninwardly offset connecting wall therebetween;

a series of spaced slots in said connecting wall; and

said second pair of brackets for said guard rail include a base flangeat one end of said arm portion with hook means extending therefrom;

said hook means including upwardly and downwardly projecting coplanarhook members the effecting lengths of which are greater than thevertical opening of said slots;

the inner surfaces of said planar hook members being spaced from saidbase flange substantially the same distances as the offset of saidconnecting wall from said pair of upright walls, whereby said hook meansof said bracket members are engageable through said slots in an upwardangular position and said inner surfaces thereof engage over the top andbottom of said slots with said base flange abutting said pair of uprightwalls of said rail members.

6. A shelf assembly in accordance with claim 3 in which:

a pair of said tubular guard rail units is provided;

Y 10 said guard rail units being substantially identical and having anencompassing wall'with over-lapping terminal edges spaced axially fromeach other and one edge being spaced inside the other to define an"elongated open-ended slot; said pair 'of guard rail units beingtelescoped one upon the other with a portion of the encompassing wall ofeach within the elongated slot of the other. 7. A shelf assembly inaccordance with claim 3 in which:

.a pair of said tubular guard rail units is provided; said rail unitsbeing identical and having an encompassing wall with over-lappingterminal edges spaced axially from each other and one edge being spacedinside the other to define an elongated open-ended slot;

said pair of guard rail units being telescoped one uponthe other with aportion of the encompassing wall of each within the elongated slot ofthe other; a; pair of said shelf units is provided as a shelf assem y;atubular flange on one side of each of said shelf units being smaller incross-sectional area than the other 7 flange; the internal opposing wallof said smaller flange having an edge defining an elongated open-endedslot along one side of saidplanar portion; the internal opposing wall ofsaid other and larger flange having an edge defining an elongatedopenended slot along the opposite side of said planar portion; said pairof shelf units being telescoped one upon the other with the smallerflange of one inside the larger flange of the other and said respectiveslots receiving the integral planar portion of the other whereby theeffective length of said shelf assembly is adjustable. 8. A shelfassembly in accordance with claim 1 in which: i

said bracket members include a transverse supporting flange coextensivewith said planar portion between said internal opposing walls; and saidtabs extend from and are coplanar with the ends of said supportingflanges. 9. A shelf assembly in accordance with claim 1 in which saidresilient sheet material is metal.

10: A shelf assembly in accordance with claim 3 in which said tabmembers on said second pair of brackets 0 comprise:

a pair of spaced individual "resilient protuberances having outwardlycurved divergent ends; said curved ends extending beyond the sides ofsaid tab members and adapted to snap-fit into the open end of saidtubular guard rail unit. 11. A shelf assembly including: I a pair ofidentical shelf units of resilient sheet material; I each of said shelfunits having a rectangular planar portion between coextensive integraltubular flanges along the longitudinal edges thereof; each of saidflanges extending above and below the plane of said planar portion andpresenting integral opposing walls on each side thereof;

one of said tubular flanges on one side of each of said shelf unitsbeing smaller in cross-sectional area than the other flange;

an internal opposing wall of said smaller flange having an edge definingan elongated open-ended slot along the one side of said planar portion;

an internal opposing wall of said other and larger flange having an edgedefining an elongated openended slot along the opposite side of saidplanar portion;

said pair of shelf units being telescoped one upon the other inover-lapping relationship with the smaller flange of one inside thelarger flange of the other and said respective slots receiving theintegral planar portion of the other whereby the effective length ofsaid pair of shelf units is adjustable.

12. A shelf assembly in accordance with claim 11 wherein:

bracket means are provided to engage the ends of said pair of telescopedshelf units to hold same in a substantially horizontal plane from asupporting vertical surface.

13. A shelf assembly in accordance with claim 11 in which:

apertures are provided in each of said internal opposing walls of saidtubular flanges adjacent to and substantially equally spaced from theends of each shelf unit; and

a pair of supporting bracket means is provided, each having oppositelydisposed pairs of transverse tab members spaced from the end of saidshelf units a distance greater than the spacing of said opposinginternal walls of said tubular flanges, whereby the resiliency of saidshelf unit allows the effective transverse span between said flanges tospread so as to engage said apertures over said pairs of tab members onthe respective bracket means.

14. In a sheet metal shelf assembly the combination a pair of identicalshelf units each having a rectangular planar portion between coextensiveintegral tubular flanges along the longitudinal side edges thereof;

one of said tubular flanges of each of said shelf units being smaller incross-sectional area than the other;

each of said flanges of a shelf unit extending above and below the planeof said planar portion and presenting internal opposing side walls oneach side thereof;

apertures in each of said internal side walls of said shelf unitsadjacent to and substantially equally spaced from the ends of said shelfunits;

said internal opposing walls of said smaller flange of each shelf unithaving an edge defining an elongated open-ended slot along one side ofsaid planar portion;

the internal opposing walls of said larger flange of each shelf unithaving an edge defining an elongated open-ended slot along the otherside of said planar portion;

said pair of shelf units being telescoped one upon the other into ashelf assembly with the smaller flange of one inside the larger flangeof the other and said respective slots receiving the integral planarportion of the other whereby the effective length of said shelf assemblyis adjustable to expose a pair of said apertures on the same side and ateach end of said shelf assembly;

a pair of bracket members having arm portions adapted to be affixed inhorizontal spaced coplanar positions from a supporting structure;

said bracket members each having a pair of transversely extending tabson the inner surface of said arm portions adapted to span between andengage within said exposed apertures of said shelf assemy;

a pair of identical tubular guard rail units;

said guard rail units having an encompassing wall with overlappingterminal edges spaced axially from each other and one edge being spacedinside the other to define an elongated open-ended slot;

said pair of guard rail units being telescoped one upon the other into aguard rail assembly with a portion of the encompassing wall of eachwithin the elongated slot of the other;

a second pair of bracket members having arm portions adapted to beaffixed in horizontal spaced coplanar position from said supportingstructure above said first pair of bracket members;

said bracket members of said second pair each having a pair of laterallyextending tabs on the inner surfaces of said arm portions adapted tospan between and engage within the extended ends of said tubular guardrail assembly.

15. A sheet metal shelf assembly in accordance with claim 14 including:

spaced upright substantially coplanar rail members are provided in fixedpositions on said supporting surface to hold said shelf assembly;

said rail members each presenting a pair of upright spaced walls with aninwardly offset connecting wall therebetween;

a series of spaced slots in said connecting wall;

said bracket members of said first pair of brackets include a baseflange at one end of said arm portion with hook means extendingtherefrom;

said hook means including a downwardly projecting portion the effectivelength thereof being longer than the vertical opening of said slots andthe inner surface of said projecting portions being spaced from saidbase flange substantially the same distance as the offset of saidconnecting wall from said pair of upright walls whereby said hook meansof said bracket members are engageable through said slots in an upwardangular position and said inner surface thereof engages over the bottomof said slots with said base flange abutting same pair of upright wallsof said rain members; and

said second pair of brackets for said guard rail include a base flangeat one end of said arm portion with hook means extending therefrom;

said hook means including upwardly and downwardly projecting coplanarhook members the effective lengths of which are greater than thevertical opening of said slots;

the inner surfaces of said planar hook members being spaced from saidbase flange substantially the same I distances as the offset of saidconnecting wall from said pair of upright walls, whereby said hook meansof said bracket members are engageable through said slots in an upwardangular position and said inner surfaces thereof engage over the top andbottom of said slots with said base flange abutting said pair of uprightwalls of said rail members.

16. In a sheet metal shelf assembly the combination a pair of identicalshelf units each having a rectangular planar portion between coextensiveintegral tubular flanges along the longitudinal side edges thereof;

one of said tubular flanges of each of said shelf units being smaller incross-sectional area than the other;

each of said flanges of a shelf unit extending above and below the planeof said planar portion and presenting internal opposing side walls oneach side thereof;

apertures in each of said internal side walls of said shelf unitsadjacent to and substantially equally spaced from the ends of said shelfunits;

said internal opposing walls of said smaller flange of each shelf unithaving an edge defining an elongated open-ended slot along one side ofsaid planar portion;

the internal opposing walls of said larger flange of each shelf unithaving an edge defining an elongated open-ended slot along the otherside of said planar portion;

said pair of shelf units being telescoped one upon the other into ashelf assembly with the smaller flange of one inside the larger flangeof the other and said respective slots receiving the integral planarportion of the other whereby the effective length of said shelf assemblyis adjustable to expose a pair of said apertures on the same side and ateach end of said shelf assembly;

a first pair of bracket members adapted to be affixed in horizontalspaced coplanar positions from a sup porting structure;

said bracket members each having tab means adapted to span between andengage said shelf assembly;

a pair of identical tubular guard rail units;

said guard rail units having an encompassing wall with over-lappingterminal edges spaced axially from each other and one edge being spacedinside the other to define an elongated open-ended slot;

said pair of guard rail units being telescoped one upon the other into aguard rail assembly with a portion of the encompassing wall of eachwithin the elongated slot of the other;

a second pair of bracket members adapted to be affixed in horizontalspaced coplanar position from said supporting structure above said firstpair of bracket members; said bracket members having tab means adaptedto span between and engage within the extended ends of said tubularguard rail assembly. 17. A sheet metal assembly in accordance with claim16 in which:

said flanges of said pair of shelf units are rectangular incross-section; said guard rail units are rectangular in cross-section;

and the edge of the outermost of said over-lapping walls of said guardrail units is rounded along its length. 18. A shelf assembly comprising:at least a pair of shelf units of resilient sheet material each having aplanar portion between coextensive integral tubular flanges alongopposite longitudinal edges thereof; one of the tubular flanges of ashelf unit being smaller and having an external cross-sectional areawhich is no greater than the internal cross-sectional area of the otherlarger tubular flange; each of said tubular flanges having an internalwall with an edge disposedin spaced relationship along said planarportion and defining an elongated open-ended slot along one side of saidplanar portion; each of said open-ended slots being transversely spacedand on opposite sides of said planar portion; one of said shelf unitsbeing telescoped upon the other with its smaller flange inside thelarger flange of the other to form an extendable shelf assembly; andmeans operative to engage said telescoped shelf units to a supportingbracket are provided at each of the extended ends of said assembly. 19.A shelf assembly in accordance with claim 18 in which:

more than a pair of said shelf units are employed in telescopingrelationship. 20. A shelf assembly in accordance with claim 18 in which:

said engaging means are provided on both ends and on opposite sides ofsaid ends whereby each of said shelf units is interchangeable and saidengaging means are exposed in any attitude of extension and on eitherside of said shelf assembly.

1. A shelf assembly including: a shelf unit of resilient sheet materialhaving a rectangular planar portion between coextensive integral tubularflanges along the longitudinal edges thereof; each of said flangesextending above and below the plane of said planar portion andpresenting internal opposing walls on each side thereof; apertures ineach of said internal walls adjacent to and substantially equally spacedfrom the ends of said shelf; and a pair of bracket members having armportions adapted to be affixed in horizontal spaced coplanar positionsfrom a supporting structure; said bracket members each having a pair oftransversely extending tabs on the inner surfaces of said arm portionsadapted to span between and engage within said apertures; and theresiliency of said shelf unit allowing the effective transverse spanbetween said flanges to be spread so as to engage said apertures oversaid pairs of tabs.
 2. A shelf assembly in accordance with claim 1wherein: a pair of said shelf units is provided as a shelf assembly; atubular flange on one side of each of said shelf units being smaller incross-sectional area than the other flange; the internal opposing wallof said smaller flange having an edge defining an elongated open-endedslot along one side of said planar portion; the internal opposing wallof said other and larger flange having an edge defining an elongatedopen-ended slot along the opposite side of said planar portion; saidpair of shelf units being telescoped one upon the other with the smallerflange of one inside the larger flange of the other and said respectiveslots receiving the integral planar portion of the other whereby theeffective length of said shelf assembly is adjustable.
 3. A shelfassembly in accordance with claim 1 including: a second pair of bracketmembers having arm portions adapted to be affixed in horizontal spacedcoplanar positions from said supporting structure above said pair ofbrackets for said shelf unit, with the extended ends thereofsubstantially coextensive therewith; said second pair of brackets eachhaving tab members extending inwardly from the inside and extended endof said arm portions along a longitudinal axis of said shelf unit; and atubular guard rail unit adapted to span between and engage at its openends over said tab members of said pair of bracket members.
 4. A shelfassembly in accordance with claim 1 in which: spaced uprightsubstantially coplanar rail members are provided in fixed positions onsaid supporting surface to hold said shelf assembly; said rail memberseach presenting a pair of upright spaced walls with an inwardly offsetconnecting wall therebetween; a series of spaced slots in saidconnecting wall; and said bracket members include a base flange at oneend of said arm portion with hook means extending therefrom; said hookmeans including a downwardly projecting portion the effective lengththereof being longer than the vertical opening of said slots and theinner surface of said projecting portions being spaced from said baseflange substantially the same distance as the offset of said connectingwall from said pair of upright walls whereby said hook means of saidbracket members are engageable through said slots in an upward angularposition and said inner surface thereof engages over the bottom of saidslots with said base flange abutting same pair of upright walls of saidrail members.
 5. A shelf assembly in accordance with claim 3 in which:spaced upright substantially coplanar rail members are provided in fixedpositions on said supporting surface to hold said shelf assembly; saidrail members each presenting a pair of upright spaced walls with aninwardly offset connecting wall therebetween; a series of spaced slotsin said connecting wall; and said second pair of brackets for said guardrail include a base flange at one end of said arm portion with hookmeans extending therefrom; said hook means including upwardly anddownwardly projecting coplanar hook members the effecting lengths ofwhich are greater than the vertical opening of said slots; the innersurfaces of said planar hook members being spaced from said base flangeSubstantially the same distances as the offset of said connecting wallfrom said pair of upright walls, whereby said hook means of said bracketmembers are engageable through said slots in an upward angular positionand said inner surfaces thereof engage over the top and bottom of saidslots with said base flange abutting said pair of upright walls of saidrail members.
 6. A shelf assembly in accordance with claim 3 in which: apair of said tubular guard rail units is provided; said guard rail unitsbeing substantially identical and having an encompassing wall withover-lapping terminal edges spaced axially from each other and one edgebeing spaced inside the other to define an elongated open-ended slot;said pair of guard rail units being telescoped one upon the other with aportion of the encompassing wall of each within the elongated slot ofthe other.
 7. A shelf assembly in accordance with claim 3 in which: apair of said tubular guard rail units is provided; said rail units beingidentical and having an encompassing wall with over-lapping terminaledges spaced axially from each other and one edge being spaced insidethe other to define an elongated open-ended slot; said pair of guardrail units being telescoped one upon the other with a portion of theencompassing wall of each within the elongated slot of the other; a pairof said shelf units is provided as a shelf assembly; a tubular flange onone side of each of said shelf units being smaller in cross-sectionalarea than the other flange; the internal opposing wall of said smallerflange having an edge defining an elongated open-ended slot along oneside of said planar portion; the internal opposing wall of said otherand larger flange having an edge defining an elongated open-ended slotalong the opposite side of said planar portion; said pair of shelf unitsbeing telescoped one upon the other with the smaller flange of oneinside the larger flange of the other and said respective slotsreceiving the integral planar portion of the other whereby the effectivelength of said shelf assembly is adjustable.
 8. A shelf assembly inaccordance with claim 1 in which: said bracket members include atransverse supporting flange coextensive with said planar portionbetween said internal opposing walls; and said tabs extend from and arecoplanar with the ends of said supporting flanges.
 9. A shelf assemblyin accordance with claim 1 in which said resilient sheet material ismetal.
 10. A shelf assembly in accordance with claim 3 in which said tabmembers on said second pair of brackets comprise: a pair of spacedindividual resilient protuberances having outwardly curved divergentends; said curved ends extending beyond the sides of said tab membersand adapted to snap-fit into the open end of said tabular guard railunit.
 11. A shelf assembly including: a pair of identical shelf units ofresilient sheet material; each of said shelf units having a rectangularplanar portion between coextensive integral tubular flanges along thelongitudinal edges thereof; each of said flanges extending above andbelow the plane of said planar portion and presenting integral opposingwalls on each side thereof; one of said tubular flanges on one side ofeach of said shelf units being smaller in cross-sectional area than theother flange; an internal opposing wall of said smaller flange having anedge defining an elongated open-ended slot along the one side of saidplanar portion; an internal opposing wall of said other and largerflange having an edge defining an elongated open-ended slot along theopposite side of said planar portion; said pair of shelf units beingtelescoped one upon the other in over-lapping relationship with thesmaller flange of one inside the larger flange of the other and saidrespective slots receiving the integral planar portion of the otherwhereby the effective length of said pair of shelf units iS adjustable.12. A shelf assembly in accordance with claim 11 wherein: bracket meansare provided to engage the ends of said pair of telescoped shelf unitsto hold same in a substantially horizontal plane from a supportingvertical surface.
 13. A shelf assembly in accordance with claim 11 inwhich: apertures are provided in each of said internal opposing walls ofsaid tubular flanges adjacent to and substantially equally spaced fromthe ends of each shelf unit; and a pair of supporting bracket means isprovided, each having oppositely disposed pairs of transverse tabmembers spaced from the end of said shelf units a distance greater thanthe spacing of said opposing internal walls of said tubular flanges,whereby the resiliency of said shelf unit allows the effectivetransverse span between said flanges to spread so as to engage saidapertures over said pairs of tab members on the respective bracketmeans.
 14. In a sheet metal shelf assembly the combination of: a pair ofidentical shelf units each having a rectangular planar portion betweencoextensive integral tubular flanges along the longitudinal side edgesthereof; one of said tubular flanges of each of said shelf units beingsmaller in cross-sectional area than the other; each of said flanges ofa shelf unit extending above and below the plane of said planar portionand presenting internal opposing side walls on each side thereof;apertures in each of said internal side walls of said shelf unitsadjacent to and substantially equally spaced from the ends of said shelfunits; said internal opposing walls of said smaller flange of each shelfunit having an edge defining an elongated open-ended slot along one sideof said planar portion; the internal opposing walls of said largerflange of each shelf unit having an edge defining an elongatedopen-ended slot along the other side of said planar portion; said pairof shelf units being telescoped one upon the other into a shelf assemblywith the smaller flange of one inside the larger flange of the other andsaid respective slots receiving the integral planar portion of the otherwhereby the effective length of said shelf assembly is adjustable toexpose a pair of said apertures on the same side and at each end of saidshelf assembly; a pair of bracket members having arm portions adapted tobe affixed in horizontal spaced coplanar positions from a supportingstructure; said bracket members each having a pair of transverselyextending tabs on the inner surface of said arm portions adapted to spanbetween and engage within said exposed apertures of said shelf assembly;a pair of identical tubular guard rail units; said guard rail unitshaving an encompassing wall with overlapping terminal edges spacedaxially from each other and one edge being spaced inside the other todefine an elongated open-ended slot; said pair of guard rail units beingtelescoped one upon the other into a guard rail assembly with a portionof the encompassing wall of each within the elongated slot of the other;a second pair of bracket members having arm portions adapted to beaffixed in horizontal spaced coplanar position from said supportingstructure above said first pair of bracket members; said bracket membersof said second pair each having a pair of laterally extending tabs onthe inner surfaces of said arm portions adapted to span between andengage within the extended ends of said tubular guard rail assembly. 15.A sheet metal shelf assembly in accordance with claim 14 including:spaced upright substantially coplanar rail members are provided in fixedpositions on said supporting surface to hold said shelf assembly; saidrail members each presenting a pair of upright spaced walls with aninwardly offset connecting wall therebetween; a series of spaced slotsin said connecting wall; said bracket members of said first pair ofbrackets include a base flange at one end of said arm portiOn with hookmeans extending therefrom; said hook means including a downwardlyprojecting portion the effective length thereof being longer than thevertical opening of said slots and the inner surface of said projectingportions being spaced from said base flange substantially the samedistance as the offset of said connecting wall from said pair of uprightwalls whereby said hook means of said bracket members are engageablethrough said slots in an upward angular position and said inner surfacethereof engages over the bottom of said slots with said base flangeabutting same pair of upright walls of said rain members; and saidsecond pair of brackets for said guard rail include a base flange at oneend of said arm portion with hook means extending therefrom; said hookmeans including upwardly and downwardly projecting coplanar hook membersthe effective lengths of which are greater than the vertical opening ofsaid slots; the inner surfaces of said planar hook members being spacedfrom said base flange substantially the same distances as the offset ofsaid connecting wall from said pair of upright walls, whereby said hookmeans of said bracket members are engageable through said slots in anupward angular position and said inner surfaces thereof engage over thetop and bottom of said slots with said base flange abutting said pair ofupright walls of said rail members.
 16. In a sheet metal shelf assemblythe combination of: a pair of identical shelf units each having arectangular planar portion between coextensive integral tubular flangesalong the longitudinal side edges thereof; one of said tubular flangesof each of said shelf units being smaller in cross-sectional area thanthe other; each of said flanges of a shelf unit extending above andbelow the plane of said planar portion and presenting internal opposingside walls on each side thereof; apertures in each of said internal sidewalls of said shelf units adjacent to and substantially equally spacedfrom the ends of said shelf units; said internal opposing walls of saidsmaller flange of each shelf unit having an edge defining an elongatedopen-ended slot along one side of said planar portion; the internalopposing walls of said larger flange of each shelf unit having an edgedefining an elongated open-ended slot along the other side of saidplanar portion; said pair of shelf units being telescoped one upon theother into a shelf assembly with the smaller flange of one inside thelarger flange of the other and said respective slots receiving theintegral planar portion of the other whereby the effective length ofsaid shelf assembly is adjustable to expose a pair of said apertures onthe same side and at each end of said shelf assembly; a first pair ofbracket members adapted to be affixed in horizontal spaced coplanarpositions from a supporting structure; said bracket members each havingtab means adapted to span between and engage said shelf assembly; a pairof identical tubular guard rail units; said guard rail units having anencompassing wall with over-lapping terminal edges spaced axially fromeach other and one edge being spaced inside the other to define anelongated open-ended slot; said pair of guard rail units beingtelescoped one upon the other into a guard rail assembly with a portionof the encompassing wall of each within the elongated slot of the other;a second pair of bracket members adapted to be affixed in horizontalspaced coplanar position from said supporting structure above said firstpair of bracket members; said bracket members having tab means adaptedto span between and engage within the extended ends of said tubularguard rail assembly.
 17. A sheet metal assembly in accordance with claim16 in which: said flanges of said pair of shelf units are rectangular incross-section; said guard rail units are rectangular in cross-section;and the edge of the outermost of said over-lapping walls of said guardrail units is rounded along its length.
 18. A shelf assembly comprising:at least a pair of shelf units of resilient sheet material each having aplanar portion between coextensive integral tubular flanges alongopposite longitudinal edges thereof; one of the tubular flanges of ashelf unit being smaller and having an external cross-sectional areawhich is no greater than the internal cross-sectional area of the otherlarger tubular flange; each of said tubular flanges having an internalwall with an edge disposed in spaced relationship along said planarportion and defining an elongated open-ended slot along one side of saidplanar portion; each of said open-ended slots being transversely spacedand on opposite sides of said planar portion; one of said shelf unitsbeing telescoped upon the other with its smaller flange inside thelarger flange of the other to form an extendable shelf assembly; andmeans operative to engage said telescoped shelf units to a supportingbracket are provided at each of the extended ends of said assembly. 19.A shelf assembly in accordance with claim 18 in which: more than a pairof said shelf units are employed in telescoping relationship.
 20. Ashelf assembly in accordance with claim 18 in which: said engaging meansare provided on both ends and on opposite sides of said ends wherebyeach of said shelf units is interchangeable and said engaging means areexposed in any attitude of extension and on either side of said shelfassembly.